How to display message persistently in echo area

[Dan Davison <davison@stats.ox.ac.uk>]

When I evaluate (message "the message"), "the message" remains in the
echo area until, for example, a key press in the current buffer.

I'd like to be write a function that behaves like message, but for
which the message does not disappear when I start typing. I want it to
go away when I next do something that actually uses the echo area /
minibuffer. What strategy do people suggest for achieving this aim? Or
have I missed something that exists already?

[The motivation is in ESS (Emacs Speaks Statistics) which has a nice
function that reminds one of function arguments in the echo
buffer. Unfortunately I've discovered that I can remember 3 function
arguments for less than a couple of seconds.]

Thanks,

Dan